System for installing fluid elements in conduit circuits

ABSTRACT

This invention relates to the construction of elements of fluid circuits such as: check valves, pressure and flow regulating valves, circuit breaking valves, restrictors, filters and the like. The construction utilizes the element housing to form a conduit fitting seat-insert. The form thereby permits the circuit element to be installed within a conduit fitting such as a union.

O United States Patent 1 1 [111 3,749,122

Gold 1 July 31, 1973 [54] SYSTEM FOR INSTALLING FLUID 2,984,261 5/1961Kates 138/46 ELEMENTS IN CONDUIT CIRCUITS 3,194,262 7/1965 Hamilton137/525 X 3,434,495 3/1969 Scaramucci 137/542 [76] Inventor: HaroldGold, 3645 Tolland 3,442,288 5/1969 Scaramucci 137/515 Shaker Heights,Ohio 44122 3,516,688 6/1970 Gachot 137/454.2 X [2 Filed: Apr. 27 19713,626,978 12/1971 Hoekstra 137/5253 PP N03 137,880 PrimaryExaminer-Martin P. Schwadron Assistant Examiner-David J. Zobkiw [52] US.Cl l37/5l5.7, 137/517, 137/542,

138/42, 138/44, 138/46, 239/453, 239/491 57 ABSTRACT [51] Int. Cl. F161:15/00 [58] Field of Search 285/D1G. 22- relates elements 5 5 5 542 5 1Offlllld Cll'CllltS such as: ChCCk valves, pressure and flOW 138 46; 29156] R, 1571 R; 220 40 A regulating valves, circuit breaking valves,restrictors,

I l filters and the like. The constmction utilizes the ele- [56]References Cited ment housing to form a conduit fitting seat-insert. Theform thereby permits the circuit element to be installed UNITEDSTATESPATENTS within a conduit fitting such as a union. 620,936 3/1899 Kunzer137/542 X 2,711,840 6/ 1955 Gits et a1. 220/42 A 7 Claims, 11 DrawingFigures Patented July 31, 1973 6M5 W7 W6 ZZZ mil" l/YWf/V TOR [AW/1.4416,

SYSTEM FOR INSTALLING FLUID ELEMENTS IN CONDUIT CIRCUITS BACKGROUND OFTHE INVENTION 1. Field of the Invention This invention provides a meansby which active and passive fluid circuit elements are installeddirectly within pipe or tube fittings.

2. The Prior Art In the present invention, utilization is made of theconduit fastening system described in my copending application Ser. No.l24,74l entitled FLUID TIGHT CONDUIT FASTENING SYSTEM, filed Mar. 16,1971. The two port elements of the present invention duplicate the outerform of the seat-inserts described in the copending application and aredirectly interchangeable therewith.

SUMMARY OF THE INVENTION The invention provides a construction throughwhich both active and passive circuit elements are contained withinseat-inserts of conduit fittings. The seat-insert form is cylindricalwith coaxial end faces. The end faces are clamped by the fittingelements and are thereby joined in fluid tight manner to a tube or pipe.The seat-insert utilizes two cylindrical parts that are joinedcoaxially. A transverse, axially perpendicular partition, which issecured between the two cylindrical parts, supports elements that coactwith passages within the insert to form the active or passive circuitelement.

As is disclosed in the Detailed Description, the invention providesmeans whereby active elements such as check valves and pressure and flowregulating valves; and, passive elements such as orifices and laminarflow type restrictors, and filters can be housed in an externallyidentical seat-insert form and thereby may-be used interchangeably in aconduit fitting. The fitting installation results in a great reductionin conduit fitting and housing components over that required withseparate element housings that utilize integral or separate conduitfittings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows a cross-sectional view ofa seat-insert type of tube union in which the seat-insert is, inaccordance with this invention, configured to form a check or reliefvalve;

FIG. 2 shows a duplicate cross-sectional view of the seat-insert shownin FIG. 1, and is included to permit clearer identification of the partsand features;

FIG. 3 shows an enlarged, fragmentary, cross-' sectional view of thejoining mechanism employed in the seat-insert shown in FIG. I and in thesubsequent figures;

FIG. 4 shows a cross-sectional view of a seat-insert that is externallya duplicate of the seat-insert shown in FIG. I and, in accordance withthis invention, is internally configured to form a fluid circuitbreaker;

FIG. 5 shows a cross-sectional view of a seat-insert that is externallya duplicate of the seat-insert shown in FIG. 1 and, in accordance withthis invention, is internally configured to form a variable-area spraynozzle; and also shows a cross-sectional view of a fitting that isconfigured to accomodate a spray nozzle;

FIG. 6 shows a duplicate cross-sectional view of the seat-insert shownin FIG. 5, and is included to permit clearer identification of the partsand features;

FIG. 7 shows a cross-sectional view of a seat-insert that is externallya duplicate of the seat-insert shown in FIG. 1 and, in accordance withthis invention, is internally configured to form a fixed-area,vortex-type spray nozzle;

FIG. 8 shows a cross-sectional view of a seat-insert that is externallya duplicate of the seat-insert shown in FIG. I and, in accordance withthis invention, is internally configured to form a flow regulator;

FIG. 9 shows a cross-sectional view of a seat-insert that is externallya duplicate of the seat-insert shown in FIG. 1 and, in accordance withthis invention, is internally configured to form a filtered, plateorifice;

FIG. 10 shows a cross-sectional view of a seat-insert that is externallya duplicate of the seat-insert shown in FIG. 1 and, in accordance withthis invention, is internally configured to form a laminar flowrestrictor; and,

FIG. 11 shows a cross-sectional view of a seat-insert that is formedthrough a dimensional variation of the internal elements of theseat-insert of FIGS. 1 and 2 and is by this means configured to form apressure responsive actuator.

DETAILED DESCRIPTION OF THE INVENTION In the description that followsall parts having the same function are identified in all figures by thesame numeral.

As described in my copending application, the flared tube unionillustrated in FIG. 1 comprises nut body 1, seat-insert 2, bored screw 3and flared tubes 4 and 4a. Seat-insert 2 is provided with equal diametercylindrical lands 5 and 5a, coaxial conical ends 6 and 6a andcylindrical groove 7 that is substantially at the mid point. The coneangles of conical end6, of the flared end 8 of tube 4 and of conicalshoulder 9 in screw 3 are substantially equal. Similarly, the coneangles of conical end 6a, of the flared end 10 of tube 4a and of conicalshoulder 11 in nut body 1 are substantially equal. Bore 12 in screw 3mates with tube 4; bore 13 in nut body 1 mates with tube 40; and bore 14and bore in seat-insert 2 provide the communicating passages between theinternal portion of seat-insert 2 and tubes 4 and 4a. The two sets ofmating cones are simultaneously clamped into sealing contact by thescrew motion of screw 3 into nut body 1.

Tubular portion 15 is integral with and projects coaxially from screw 3,The outer diameter of tube 15 is equal to or smaller than the rootdiameter of the threads of screw 3 and the bore 16 is slightly largerthan the diameter of lands 5 and 5a. The wall of tube 15 is providedwith a pair of diametrically opposite indentations 17 and 17a. Thediametral distance between innermost points of indentations I7 and 17ais smaller than the diameter of lands 5 and 5a, but is greater than thediameter of groove 7. The diameter of the indentations 17 and 17a isless than the width of groove 7. Accordingly seat-insert 2 is permittedto move axially and laterially within this attachment for clampingalignment, but remains attached to screw 3 upon disconnection of screw 3from nut body 1. During insertion into or removal of seat-insert 2 frombore 16 through the application of an axial force between seat-insert 2and screw 3 tube 15 elastically deforms into oval shape when theindentations I7 and 17a contact land 5. The

oval deformation is permitted by the clearance between bore 16 and land5.

A seatinsert ofthe present invention, shown in FIGS. 1, 2 and 3, is madeof two shells 18 and 19 that join at one side of groove 7. Coaxial bore20 in shell 18 terminates at one end at conical seat 21 and at theopposite end in counterbore 22. Conical seat 21 converges from thediameter of bore 20 to the diameter of bore 14a. Adjacent to counterbore22 and contiguous with groove 7, shell 18 is provided with land 23.Counterbore 24 of shell 19 mates with land 23 to attach shell 19 toshell 18. Conical bore 25 of shell 19 expands from the diameter of bore14 to approximately the diameter of bore 20 and terminates atcounterbore 24. Cylindrical partition 26 fits in counterbore 24 and islocked therein by the attachment of shell 19 to shell 18. Valve guide 27is integral with or is secured to partition 26 and is held coaxial withbore 20 and conical seat 21 thereby. Valve stem 28 mates slideably withcoaxial bore 29 in valve guide 27. Valve head 30 is integral with or issecured to stem 28 and is provided with conical face 31 that mates insealing relationship with seat 21, Spring 32 seats against partition 26and valve head 30 to urge valve head 30 into contact with seat 21. Holes33 in partition 26 provide the flow path between bore 20 and conduit 4.The diameter of valve head 30 is less than the diameter of bore 20. Whenthe pressure in conduit 40 exceeds the pressure in conduit 4 by anamount that is sufficient to overcome the force of spring 32 conicalface 31 is moved away from seat 21 and fluid from conduit 4a flowsaround head 30, into bore 20, and through holes 33 into conduit 4.

In the installed position shown in FIG. 1 shell 19 is held in attachmentwith shell 18 by the clamping action ofthe tube attachment mechanism.However, when tbe valve configuration of seat-insert 2 is not held in afit ting assembly spring 32 urges shells 18 and 19 apart. Therefore, forconvenience of handling, it is preferable to provide an independentattachment mechanism to hold the seat-insert assembled. The fasteningmethod shown in the enlarged view of FIG. 3 is compatible with thefunctional requirements and permits a high rate of assembly.

In the mechanism shown in FIG. 3 land 23 is provided with a taper thatconverges toward groove 7. In the preattached condition, indicated bythe dashed lines, counterbore 24 of shell 19 is cylindrical and isadapted to slip freely over the maximum diameter of conical land 23; andland is conical. The cone angle of land 5 in the preattached conditionis substantially the same as the cone angle of tapered land 23. Whenconical land 5 is swaged into cylindrical form by being pressed througha cylindrical die, or compressed in rolls, bore 24 is made conical andmates in locking relationship with conical land 23. Cylindricalpartition 26 radially stiffens land 23 against the swaging forces. Asecure lock is thereby provided and deformation of bore is prevented. Asmay be seen in the enlarged view, the parts 18 and 19 are joined in theaxially perpendicular plane defined by the surface 26a of partition 26,and 18a of part 18 and the annular surface 19a of part 19.

The seat-insert illustrated in FIG. 4 is interchangeable with theseat-insert shown in FIG. 1 with respect to forming a seal against theflared ends of tubes 4 and 40, but is internally configured to stop theflow from conduit 40 to conduit 4 when the rate of flow exceeds a presetlimit. Valve head 30 is provided with conical shoulder 34 and cylinder35. Spring seat 36 is a shouldered washer that slips over stem 28 andrests against the shoulder formed by cylinder 35. Spring 32 seatsagainst seat 36 and partition 26 and thereby urges head 30 outward.Washer 37 is retained by snap ring 38 and seats against partition 26,thereby limiting the outward position of head 30. Conical shoulder 34mates with conical seat 39. Under the condition of flow from conduit 4ato conduit 4 at flow rates below the preset limit the valve elements areas shown in FIG. 4. In this case flow from conduit 4a passes through theannular orifice formed between bore and cylinder 35, through bore 20,holes 33, bore 14 and into conduit 4. When the rate of flow reaches apreset value the pressure drop across the annular orifice acting on thevalve assembly, generates an axial force that is greater than the forceexerted by spring 32. When this occurs, conical shoulder 34 moves towardseat 39 thereby increasing the flow resistance of the assembly and anincreased pressure drop occurs across the valve assembly. This wellknown, statically unstable condition results in rapid seating ofshoulder 34 against seat 39 and the flow is stopped.

In the flow condition the area of the annular orifice that is formedbetween bore 140 and cylinder 35 is substantially smaller than the areabetween conical shoulder 34 and seat 39. The controlling annular area isreadily manufactured to high accuracy and is unaffected by axialdimensional variations. This factor permits the shut-off flow conditionto be set accurately.

The seat-insert illustrated in FIGS. 5 and 6 is interchangeable with theseat-insert shown in FIG. 1 with respect to the forming of a sealagainst the flared ends of tube 4 and 40 but is configured in adifferent manner to form a check or relief valve; but, is moreparticularly configured to form a pintle-type spray nozzle, for whichpurpose it is installed in a fitting such as shown in FIG. 5. In theassembly of FIG. 5, seat-insert 2 is clamped between the flared end 8 oftube 4 and conical seat 40 in nut body 1. As is readily apparent fromFIGS. 5 and 6 and from the foregoing description stem 28 passes throughpartition 26 and spring 32 seats against partition 26 and washer 37,thereby urging shoulder 34 of head 30 into sealing contact with seat 39.When the pressure in conduit 4 exceeds the pressure external of nut body1 in FIG. 5 by an amount that is sufficient to overcome the axial springforce, conical shoulder 34 is moved away from seat 39 and fluid flowsfrom conduit 4, through bore 14, holes 33, bore 20 and discharges in aconical sheet from the conical annulus formed between shoulder 34 andseat 39. Conical recess 41 in nut body 1 provides the necessaryclearance for the emis sion of the spray.

The seat-insert illustrated in FIG. 7 is interchangeable with theseat-insert shown in FIG. 5 with respect to forming a seal against theflared end of tube 4 and seat 40, and also with respect to the formationof a conical spray. In the seat-insert of FIG. 7 partition 26 isintegral with coaxial cylinder 42. Conical end 43 of cylinder 42 seatsagainst conical seat 21 and is pressed into this contact by theattachment of shell 19 to shell 18. Coaxial bore 44 and radial bores 45provide the flow path from bore 14 to bore 20. Cylindrical chamber 46communicates with bore 20 through holes 47 that are tangential tochamber 46. By the well known action the flow discharging through holes47 causes a rotational flow in chamber 46, which upon dischargingthrough bore I4a, forms a hollow conical spray.

The seat-insert illustrated in FIG. 8 is interchangeable with theseat-insert shown in FIG. I with respect to forming a seal against theflared ends of tubes 4 and 40, but is internally configured to form aflow regulator. Piston 48 fits slideably in bore 49 and has a coaxialbore 50 and a head 51. Partition 26 includes integral cone 52. The baseof cone 52 is flat and is recessed to hold spring 32 in coaxialposition. Holes 33 are tangent to cone 52 at its junction with thecylindrical portion of partition 26. The diameter of the base of cone 52is greater than the diameter of piston 48 but is less than the diameterof bore 20. The diameter of bore 14a is less than the diameter of bore49, a shoulder 53 being form at the intersection. Orifice 54 providesthe fluid passage through head 51 of piston 48. Spring 32 seats againstthe inner side of head 51 and thereby urges piston 48 toward shoulder53. The open area of variable orifice 55, which is the cylindrical gapbetween the openend of piston 48 and the flat base of cone 52, isreduced as piston 48 moves toward the base of cone 52. Flow fromvariable orifice 55 passes into bore 20 and through holes 33 and bore14. With the seat-insert 2 of FIG. 8 installed in the union of FIG. 1the direction of regulated flow is from conduit 4a to conduit 4. Inaccordance with the well known principal of regulation, the pressuredrop across orifice 54 is maintained substantially constant by thevariation of the area of orifice 55 through the axial movement of piston48 inresponse to the pressure and spring forces.

The seat-insert illustrated in FIG. 9 is interchangeable with theseat-insert shown in FIG. 1 with respect to forming a seal against theflared ends of tubes 4 and 4a, but is internally configured to form afilter or a filtered orifice. Partition 26 comprises orifice plate 26aand filter ring 26b. Filter element 56 is suitably fastened to ring 26band is held coaxially in bore 20 thereby. Flow enters through bore 14a,flows through filter element 56, through orifice 57 and exits throughorifice l4. Orifice plate 26 is made separate from ring 26b for theconvenience of forming the orifice by punching. Where a thin plateorifice is not required orifice plate 26a and ring 26b may be common andorifice 57 formed by drilling. Furthermore, if orifice 57 is enlarged tosubstantially the diameter of opening of ring 26b, the assembly of FIG.9 becomes simply a filter.

The seat-insert illustrated in FIG. is interchangeable with theseat-insert shown in FIG. I with respect to forming a seal against theflared ends of tubes 4 and 4a, but is internally configured to form alaminar flow restriction. Cylinder 58 is joined to partition 26 by cone59 and is held thereby in coaxial position in bore 14a. The diameter ofbore 14a is slightly larger than the diameter of cylinder 58, thediametral clearance being set to the flow resistance desired. Bore andholes 33 provide the flow path from the annular clearance to bore 14. Asis well known, the flow may be in either direction and the length ofcylinder 58 may be greater or less than the length of bore 114a. I

The family of fluid circuit elements described thus far have operated invarious manners on the flow through the seat-insert. The seat-insert ofFIG. 11 utilizes the internal elements of the seat-insert of FIGS. 1 and2 to form a fluid circuit element that provides a rod displacement inresponse to the difference in pressure at the end faces. Thisconfiguration finds utility for interha] actuation such as is employedin pilot operated check valves. In the seat-insert of FIG. ll head 30 ismade of larger diameter than that shown in FIGS. I and 2, and stem 28 ismade longer. As shown in FIG. 11 the diameter of head 30 mates with bore20 to form a piston; and the increased length of stem 28 projects itthrough partition 26 and beyond bore 14. The relatively short actuatorstroke shown in FIG. 11 is sufficient for such operations as required inpilot operated check valves. Where longer stroke is required the lengthofguide 27 can be shortened; or alternately, partition 26, with theattached guide 27, can be installed in the turned-around position,thereby projecting guide 27 through bore 14.

For conciseness, reference has been made only to seat-inserts havingsealing faces that are adapted to mate with flared tubes or conicallyfaced flanges; and, the installation of the seat-insert has been shownonly in a tube union. However, as will be readily understood by thoseskilled in the art, the seat-insert construction of this invention canbe employed with the other sealing face arrangements shown in mycopending application, referenced above, and to the conduit-to-bodyassemblies disclosed in that application.

What is claimed is;

1. A seat member for a conduit assembly, said seat member having acoaxial pair of end faces, saidend faces forming sealing surfaces thatmate with the conduit ends, said end faces being spaced apart by asubstantially cylindrical body, said body being substantially coaxialwith said end faces, said seat member hav ing:

a. a first part and a second part, said parts being joined in a planethat is perpendicular to the axis of said end faces;

b. said first part having a plurality of bores in expanding sequence,the smallest of said bores opening at the end face of said first partand the largest of said bores opening at said perpendicular plane,adjacent bores being connected by annular surfaces;

c. said second part having a bore that opens at the end face of saidsecond part and having a passage that communicates said bore with saidperpendicular plane;

d. a conical land on said first part radially adjacent said largestbore, the diameter of said land being greatest at said perpendicularplane, and a conical bore in said second part, said conical bore matingwith said conical land and forming a locking grip therewith;

e. a partition that fits in said largest bore of said first part, saidpartition being held therein by the joining of said parts, through holesbeing in said partition, said holes providing the flow path across saidpartition;.and,

f. means coacting with said partition, said means being adapted toprovide a pressure-responsive, spring-biased fluid circuit element thatoperates on the flow between said end fees.

2. The seat member of claim I wherein said means coacting with saidpartition comprises:

a. a tubular member that is fastened to said partition, the bore of saidtubular member being continued through said partition;

b. a valve member having a stem and a head, the stem of said valvemember being guided in the bore of said tubular member and the head ofsaid valve member having a face that mates with and faces the annularsurface that is contiguous with said smallest bore;

c. a compression spring, said spring being compressed between said headand said partition and thereby acting to urge said face of said valvetoward said annular surface that is contiguous with said smallest bore.

3. The seat member of claim 1 wherein said means coacting with saidpartition comprises:

a. a tubular member that is fastened to said partition, the bore of saidtubular member being continued through said partition;

b. a valve member having a steam and a head, the stem of said valvemember being guided in the bore of said tubular member and extendingthrough said bore in said end face of said first part, the head of saidvalve member having a sealing portion that faces the end face of saidfirst part and is adapted to mate with said end face of said first part,the diameter of said head being greater than the diameter of said borein said end face of said first part and smaller than the diameter ofsaid end face of said first part; and,

c. a compression spring, said spring being compressed between said headand said partition and thereby acting to urge said head away from saidend face of said first part.

4. The seat member of claim 3 further including a cylindrical portionbetween said stem and said head of said valve member, the diameter ofsaid cylindrical portion being larger than the diameter of said stem butsmaller than the diameter of said bore in said end face of said firstpart.

5. The seat member of Claim 1 wherein said means coacting with saidpartition comprises:

a. a tubular member that is fastened to said partition, the bore of saidtubular member being continued through said partition;

b. a valve member having a stem and a head, the stem of said valvemember being guided in the bore of said tubular member and extendingthrough said bore in said end face of said first part, the head of saidvalve member having a sealing portion that faces the end face of saidfirst part and is adapted to mate with said end face of said first part,the diameter of said head being greater than the diameter of said borein said end face of said first part and smaller than the diameter ofsaid end face of said first part, and said stem projecting through saidpartition and terminiating with a flange; and,

c. a compression spring, said spring being compressed between saidpartition and said flange and thereby acting to urge said head towardsaid end face of said first part.

6. The seat member of claim 5 wherein said head of said valve member isadapted to mate with a conical recess that is contiguous with said borein said end face of said first part.

7. The seat member of claim 1 wherein said plurality of bores in saidfirst part comprises a coaxial array of a first bore, a second bore, athird bore and a fourth bore; said first bore being said smallest bore,and wherein said means coacting with said partition comprises:

a. a conical frustum member that is fastened to said partition and whichflares outwardly therefrom and projects part-way into said third bore,the diameter of the lower base end of said conical frustum being lessthan the diameter of said third bore but greater than the diameter ofsaid second bore, said through holes in said partition being outside theupper base of said conical frustum;

b. a hollow piston that mates slideably in said second bore, the openend of said piston coacting with the lower base end of said conicalfrustum to form a variable orifice, and the head of said piston havingan orifice bore; and,

c. a compression spring, said spring being compressed between said baseend of said conical frusturn and the inner face of said head of saidpiston and thereby acting to urge said piston away from said conicalfrustum member.

1. A seat member for a conduit assembly, said seat member having acoaxial pair of end faces, said end faceS forming sealing surfaces thatmate with the conduit ends, said end faces being spaced apart by asubstantially cylindrical body, said body being substantially coaxialwith said end faces, said seat member having: a. a first part and asecond part, said parts being joined in a plane that is perpendicular tothe axis of said end faces; b. said first part having a plurality ofbores in expanding sequence, the smallest of said bores opening at theend face of said first part and the largest of said bores opening atsaid perpendicular plane, adjacent bores being connected by annularsurfaces; c. said second part having a bore that opens at the end faceof said second part and having a passage that communicates said borewith said perpendicular plane; d. a conical land on said first partradially adjacent said largest bore, the diameter of said land beinggreatest at said perpendicular plane, and a conical bore in said secondpart, said conical bore mating with said conical land and forming alocking grip therewith; e. a partition that fits in said largest bore ofsaid first part, said partition being held therein by the joining ofsaid parts, through holes being in said partition, said holes providingthe flow path across said partition; and, f. means coacting with saidpartition, said means being adapted to provide a pressure-responsive,spring-biased fluid circuit element that operates on the flow betweensaid end faes.
 2. The seat member of claim 1 wherein said means coactingwith said partition comprises: a. a tubular member that is fastened tosaid partition, the bore of said tubular member being continued throughsaid partition; b. a valve member having a stem and a head, the stem ofsaid valve member being guided in the bore of said tubular member andthe head of said valve member having a face that mates with and facesthe annular surface that is contiguous with said smallest bore; c. acompression spring, said spring being compressed between said head andsaid partition and thereby acting to urge said face of said valve towardsaid annular surface that is contiguous with said smallest bore.
 3. Theseat member of claim 1 wherein said means coacting with said partitioncomprises: a. a tubular member that is fastened to said partition, thebore of said tubular member being continued through said partition; b. avalve member having a steam and a head, the stem of said valve memberbeing guided in the bore of said tubular member and extending throughsaid bore in said end face of said first part, the head of said valvemember having a sealing portion that faces the end face of said firstpart and is adapted to mate with said end face of said first part, thediameter of said head being greater than the diameter of said bore insaid end face of said first part and smaller than the diameter of saidend face of said first part; and, c. a compression spring, said springbeing compressed between said head and said partition and thereby actingto urge said head away from said end face of said first part.
 4. Theseat member of claim 3 further including a cylindrical portion betweensaid stem and said head of said valve member, the diameter of saidcylindrical portion being larger than the diameter of said stem butsmaller than the diameter of said bore in said end face of said firstpart.
 5. The seat member of Claim 1 wherein said means coacting withsaid partition comprises: a. a tubular member that is fastened to saidpartition, the bore of said tubular member being continued through saidpartition; b. a valve member having a stem and a head, the stem of saidvalve member being guided in the bore of said tubular member andextending through said bore in said end face of said first part, thehead of said valve member having a sealing portion that faces the endface of said first part and is adapted to mate with said end face ofsaid first part, the diameter of said head being greater than thediameTer of said bore in said end face of said first part and smallerthan the diameter of said end face of said first part, and said stemprojecting through said partition and terminiating with a flange; and,c. a compression spring, said spring being compressed between saidpartition and said flange and thereby acting to urge said head towardsaid end face of said first part.
 6. The seat member of claim 5 whereinsaid head of said valve member is adapted to mate with a conical recessthat is contiguous with said bore in said end face of said first part.7. The seat member of claim 1 wherein said plurality of bores in saidfirst part comprises a coaxial array of a first bore, a second bore, athird bore and a fourth bore; said first bore being said smallest bore,and wherein said means coacting with said partition comprises: a. aconical frustum member that is fastened to said partition and whichflares outwardly therefrom and projects part-way into said third bore,the diameter of the lower base end of said conical frustum being lessthan the diameter of said third bore but greater than the diameter ofsaid second bore, said through holes in said partition being outside theupper base of said conical frustum; b. a hollow piston that matesslideably in said second bore, the open end of said piston coacting withthe lower base end of said conical frustum to form a variable orifice,and the head of said piston having an orifice bore; and, c. acompression spring, said spring being compressed between said base endof said conical frustum and the inner face of said head of said pistonand thereby acting to urge said piston away from said conical frustummember.